An automatic control system for extracorporeal gas exchange support is presented. A microcomputer-based data acquisition, analysis, and feedback control system will be developed to control extracorporeal oxygen delivery (by adjusting extracorporeal blood flow) and carbon dioxide removal (by adjusting gas flow through the oxygenator). Such a system is expected to improve the efficacy of oxygen delivery to the patient, maintain metabolic levels with more precision than the manually-controlled system, and provide for automatic weaning of extracorporeal support as patient condition improves. Prolonged extracorporeal life support currently requires continuous supervision in the intensive care unit by a specially-trained technician. Such supervision is very expensive, and limits the number of patients who can be supported, due to the finite number of technicians at each hospital. An automatic control system would enable one technician to oversee more than one case simultaneously. An automatic control scheme will be developed and tested using continuous recordings of data from patients during extracorporeal gas exchange support. The system will be tested with an in vitro patient model, during simulations of events possible during support, such as oxygenator failure and changes in patient oxygen requirements.